Ringless Quadrupole Configuration with Spiral Windings

Toroidal configurations with a quadrupole-like separatrix are discussed. The configurations are produced by superposing a quadrupole field and a pair of radial transform fields on a toroidal field. They may have magnetic shears close to unity. The radial transform fields are produced by planer spiral coils which may be fabricated much more accurately than toroidal-helical coils and also leave the side of the torus accessible.